Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/08/21

Area Forecast Discussion
National Weather Service Bismarck ND
938 PM CDT Fri May 7 2021 .UPDATE... Issued at 932 PM CDT Fri May 7 2021 With relative humidity values in the 20 to 30 percent range across the west, the Red Flag Warning was allowed to expire. It remains fairly windy however with most sites in the 15 to 25 mph range. We increased magnitude slightly through tonight using bias corrected short term guidance. The additional change with this update was to increase PoPs slightly on the northeast gradient using recent NBM and time lagged HRRR guidance. Thunderstorm chances in the southwest tonight were maintained, with several thunderstorms currently in southeast Montana. Strong ascent associated with the upstream trough and steep mid-level lapse rates will provide adequate elevated instability and forcing for at least a slight chance of thunder, even with the loss of insolation. UPDATE Issued at 708 PM CDT Fri May 7 2021 For near-term concerns, the Red Flag Warning continues until 02Z, when relative humidity should increase as surface temperatures decrease. A pressure gradient associated with a deepening surface low to the southwest will maintain southeasterly winds through the night, especially in our southwest where sustained winds of 20 to near 30 mph are currently being reported. Composite radar shows some light echoes over Sidney, MT and into far western North Dakota. Ceilings around 110k feet and a very dry-subcloud layer is likely preventing any rain from nearing the surface, thus maintained previous shift`s precipitation chances which don`t increase until later this evening. && .SHORT TERM...(This evening through Saturday) Issued at 213 PM CDT Fri May 7 2021 Main forecast issue in the short term period will be precipitation chances and qpf amounts. An upper level low currently moving off the Eastern Pacific and onto the Pacific Northwest coast will bring rain and snow chances to western and central North Dakota after midnight over the far west, and then Saturday and Saturday night for much of western and central North dakota. At this time it looks like areas from Williston to Bismarck and Linton and Ashley will see a majority of the precipitation, with a quick transition to little or no precipitation as you move east of this line. There is enough fg forcing late tonight within an area of strong upper level divergence, there may be some embedded thunder over southwest North Dakota. Within the area of strongest forcing, there could be some precipitation amounts greater than an inch of qpf. This most favored area of forcing (southeast McKenzie through southern Dunn and eastern Stark and into Grant county) could also see enough dynamic cooling to change precipitation to snow, and then that may limit overall qpf amounts a bit. Either way it looks like high probabilities of significant qpf over much of western and south central ND, generally along and southwest of the Missouri River. Probably the biggest change from previous runs, is the continued eastward trend in the qpf. The GFS looks to be too far east, bringing qpf well east of Minot. This is much farther east than other deterministic models. Even the NAM keeps Minot dry Saturday. GFS forecast soundings show strong forcing around 700mb and above but with quite a dry layer below this. GFS seems to be producing qpf within an are of 700 mb fg forcing but not accounting for the dry layer below this. Farther south, the NAM and GFS seem to be too far east with the qpf along the SD border. This is also shown in some of the mesoscale models. but they also keep the heavier precip west of the Missouri River. The NAM Nest, HiRes NMM and ARW are examples. Even The Canadian and ECMWF have trended a little farther east, along the SD border, but the GFS and NAM (along with HiRes NMM) are by far the farthest east, along and just north of the SD border. In addition, there is still a wide envelope of solutions within the GEFS plumes at KDIK, KXWA and KBIS. Therefore we will continue to lean on a probabilistic approach within our messaging this afternoon. Precipitation continues Saturday night and Sunday but is much lighter and tapers off from north to south as the upper to our west starts to drop south. .LONG TERM...(Saturday night through Friday) Issued at 213 PM CDT Fri May 7 2021 The upper low to our west drops south on Sunday as high pressure builds over the area from Canada. Light precipitation tapers from north to south through the day. Mainly dry conditions are expected to begin the work week. It will also be cold Monday morning with lows mainly in the 20s. Tuesday morning will also be cold, but not quite as cold as Monday. There area some model differences mid week with the aforementioned upper low and how much it might influence precipitation chances as it lifts northeast into the Great Lakes region. At this time it look mostly like small precipitation chances at best as it tracks by Tuesday night and Wednesday. After a cool start to the week with highs mainly in the 50s and lower 60s Monday through Wednesday, we do see some 70 degree readings towards the end of the work week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 708 PM CDT Fri May 7 2021 VFR conditions to begin the 00Z TAF period. Widespread MVFR to IFR ceilings and visibilities will move into the forecast area from west to east beginning early Saturday morning, with conditions deteriorating at KXWA-KDIK around 12Z, then KBIS around 14Z. Much less certainty exists about conditions at KMOT-KJMS with recent data showing system may stall around or just up to KMOT-KJMS. Those areas that do see MVFR to IFR cigs can expect these conditions to last through the remainder of the TAF period after they begin. Strong east to southeast flow through the forecast period west and increasing easterly flow east. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AE SHORT TERM...TWH LONG TERM...TWH AVIATION...AE
Area Forecast Discussion
National Weather Service Cheyenne WY
535 PM MDT Fri May 7 2021 .SHORT TERM...(This evening through Saturday) Issued at 231 PM MDT Fri May 7 2021 Key Messages: 1) Marginal Risk of strong to briefly severe storms this afternoon and early evening. 2) Cold front will move through the region Saturday morning with cooler daytime temperatures and scattered light rain showers. Weather Details: Water vapor and RAP analysis depicts a H7-H5 embedded impulse within the mean ridge pattern now crossing the Rockies and aiding in weak mid and upper level ascent. This dynamic ascent is coupled with weak thermodynamic buoyancy aching along and east of a pseudo-dryline from Kimball to Torrington to Douglas. Surface dewpoints west of the line are in the mid to upper 20s and east are in the low to mid 40s. The higher dewpoints are aiding in surface-based instability of 500-1000 J/Kg with 0-6km shear of 40-45 knots. Deep updrafts are not expected this afternoon but one or two storms could become briefly strong to severe with pea to quarter hail and winds of 40-60 mph very locally. Greatest likelihood for a strong storm will be from Kimball NNW to Torrington to Scottsbluff to Bridgeport to Sidney area from 4-8pm. Low end of the hazard probability envelop suggests perhaps one SPS for strong storms (HRRR based) and higher end envelope could be 3-5 SPSs and a brief SVR Warning being possible (NAM3km based). Slightly tilted in the middle or towards the HRRR as NAM3km may be too high on initializing surface dewpoints with HRRR lower but slightly mixing them out a bit too much. Somewhere between both solutions seems most likely. Convection that does develop will weaken after 9pm as instability decreases. A shortwave trough now over MT and Canada will progress southeast overnight into Saturday morning and user in a cold front across the region. Low clouds will initially follow in the wake of the front but should mix out through the day. Did decrease precipitation chances from previous official forecasts as some slight scattered showers will be possibly post-frontal under the cooler core of the mid-level low. Cooler temperatures and more clouds expected Saturday but still an overall pleasant day with north to northwest winds. .LONG TERM...(Sunday night through Thursday) Issued at 307 AM MDT Fri May 7 2021 Main forecast concern in the long range continues to be the slow moving Pacific storm system which is forecast to stall over Idaho/Montana early next week. Limited forecast confidence Sunday night through Tuesday, but confidence is increasing that most of the region will see widespread precipitation with the potential for accumulating snow above 5500 feet, and heavy snow above 7500 feet. Models have continued to trend colder on late Sunday through Tuesday as well, with model soundings showing several hours of accumulating snowfall during the night time periods. The primary storm system will begin to move east early Monday morning as it dips southward into the northern Great Basin region and southern Idaho. Models continue to show a large area of WAA aloft/overrunning, with upslope flow near the surface and diffluent flow at Jet Stream level. This is a favorable pattern, in the spring, for decent precipitation values and precip rates. However, not quite buying into the large total QPF amounts that the previous GFS has shown. Generally, the last few ensemble runs are showing these solutions as the outliers as well. Expect mostly moderate precipitation rates Monday and Tuesday with some brief breaks in between due to positioning of the short wave activity. Temperatures are expected to be much below seasonal averages between Sunday through Tuesday night as the Pacific system takes its time drifting southeast, and then eventually east, across the area. Continued to lower daytime highs into the 30s, especially across southeast Wyoming, and also lowered nighttime min temperatures into the 20s. Based on current GFS soundings, these numbers may be too high. With all this in mind, believe accumulating snowfall is a real possibility across the high valleys and eastern plains down to about 5000 to 5500 feet. Lowered snow levels and will start wording the forecast (Sunday night through Tuesday) for snow instead of just rain. By Wednesday and Thursday, Models in agreement showing the system slowly moving east out of the forecast area. Expect much warmer temperatures and decreasing cloudiness through Thursday of next week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 530 PM MDT Fri May 7 2021 VFR conditions across SE WY and W NE with mid-to-high level clouds continuing to build in to the area through this evening into tonight. Some thunderstorms are moving through W NE. There is a potential for IFR level ceilings in W NE around 9Z, but there should be more clarity on the location and spread in the next few hours. && .FIRE WEATHER... Issued at 231 PM MDT Fri May 7 2021 Elevated to near critical fire weather conditions ongoing across southeast Wyoming and the Nebraska Panhandle with winds of 20 to 30 mph and relative humidities falling into the teens and 20s. Slightly higher humidity values are occurring in Nebraska, with fuels deemed ready to burn while values in Wyoming are lower but fuels are determined not ready at this time. Otherwise, red flag conditions would be briefly met in Wyoming this afternoon. Fire weather conditions will decrease into Saturday and Sunday as a cold front moves through the region. Cooler temperatures and higher moisture will preclude fire weather concerns. Wetting rain snow is likely Sunday night, especially Monday, and ending Tuesday next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...JSA LONG TERM...TJT AVIATION...LK FIRE WEATHER...JSA
Area Forecast Discussion
National Weather Service Dodge City KS
620 PM CDT Fri May 7 2021 ...Updated Aviation... .SHORT TERM...(This evening through Saturday) Issued at 305 PM CDT Fri May 7 2021 Models show a swath of increasing MLCAPE over the southwest counties, mainly south of Highway 400, of up to around 1500 J/kg as convective elements are already beginning to develop east of the I-25 corridor. Several runs of the HRRR have been consistent in developing high based convection to around Elkhart as early as 3 pm, and more or less driving clusters of storms eastward through about Meade county by 00Z with localized downbursts, in most cases, south of the state line. Some HRRR runs have produced the best severe downbursts later temporally than any of the earlier runs, much farther east over the Comanche and Barber county areas in the mid evening. Widespread outflow over the southwest counties will race northward cooling temps off more rapidly than the typical diurnal curve this evening. Temperatures should fall to the mid and upper 50s over the southwest counties while remaining summer like in the southeast counties as convection would be yet to arrive if at all. Little overall change in the expectations for Saturday other than a trend for the risk areas to be pulled farther westward for hail, wind as well as 2% and 5% tornado risk areas. The left exit region of a southern high plains upper jet will provide ample upper flow for strengthening of a weak prefrontal 850-surface layer low pressure during the afternoon. The setup is essentially a dryline/cold front intersection over our easternmost counties, where with potential for all modes can be possible, with less of a tornado threat farther west where storms may even be post frontal. .LONG TERM...(Saturday night through Friday) Issued at 305 PM CDT Fri May 7 2021 The surface front plunges clear through the area by early evening saturday, and the rest of the forecast period through mid week is a trending colder forecast. Synoptic scale cyclonic flow covers the entire western 2/3rds of the country on Sunday, while a polar low over eastern canada draws cool air over the upper Midwest and Plains though Tuesday. Fast upper flow, with probably a number of embedded waves should transverse our region, bringing low CAPE setup showers and thunderstorms initially on Monday/Monday night, with perhaps subsequent rounds through mid week as the upper trough shifts eastward and northwest flow aloft becomes established over Kansas. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 617 PM CDT Fri May 7 2021 VFR flying conditions are expected for all terminals this TAF period. Radar observations show showers just across the border into OK near LBL, so included VCSH for the first hour for LBL. Overnight tonight, a southwesterly low-level jet will intensify across southwest Kansas bringing LLWS to all terminals from 04-07Z through 14Z. Winds will be generally light to moderate through mid-morning Saturday before increasing into the 14-20 kt range with gusts of 23-30 kts in response to a deepening lee cyclone in eastern CO. Late in the period, a cold front will drop south across southwest Kansas which will veer winds around to northerly. Thunderstorm development is likely along and ahead of this front in the 20-22Z time frame Saturday, but only included VCTS in the HYS TAF where the highest confidence in terminal impacts reside. && .PRELIMINARY POINT TEMPS/POPS... DDC 57 90 47 65 / 10 20 30 0 GCK 55 89 45 65 / 10 30 30 0 EHA 56 91 46 68 / 20 10 20 10 LBL 55 92 46 69 / 30 10 20 0 HYS 53 85 45 61 / 0 40 50 0 P28 58 90 53 68 / 30 10 20 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Springer
Area Forecast Discussion
National Weather Service El Paso TX/Santa Teresa NM
548 PM MDT Fri May 7 2021 .AVIATION...00Z TAF CYCLE... Generally VFR. Northwest of a line from El Paso-Pinon...SCT/BKN120 until 02Z, then SKC. From El Paso-Pinon southeast...BKN090CB BKN200 isolated -TSRA until 03Z, then SKC-FEW100. Small hail and wind gusts to 45KTS near storms. Otherwise surface winds southwest 10-15KTS gusts to 25KTS til 03Z then southwest 6-10KTS. Winds increasing back to southwest 15-20KTS gusts to 25KTS after 18Z. && Hefner .PREV DISCUSSION...239 PM MDT Fri May 7 2021... .SYNOPSIS... We will see a slight chance for evening thunderstorms for locations east of the Rio Grande today. On Saturday, we will be drier, but we will also be windy with some patchy areas of blowing dusty. For Sunday through Wednesday, we will be dry with breezy to windy conditions each afternoon. On Thursday, moisture will begin to trickle back into the area and on Friday we will see a slight chance for afternoon and evening thunderstorms. High temperatures for most of next week will be near what we expect this time of year. && .DISCUSSION... .SHORT TERM...Rest of Today through Saturday... Southerly flow underneath an upper level ridge continues to advect warm air and moisture into the Borderland. Daytime heating has created instability across portions of the area, with MUCAPES currently between 500-1500 J/kg and LIs between -3 and -5, with the highest values over eastern areas. Surface dewpoints across eastern areas are in the low to mid 40s, with mid to upper 30s out west. A weak shortwave is working its way into the area, which is providing an additional source of lift for this convection. Models agree that the best chance for storms currently is over the mountains, which we`re seeing on radar now. Convection is then expected to develop over northern Chihuahua, Mexico over the next hour or two and move to the northeast. This is where the high resolution models differ slightly, in regards to just how far west this convection will reach. The HRRR is the only model bringing rain/storms into El Paso around 3-4pm, while the other models continue to keep storm chances just east of El Paso. What`s for sure is that the best chance for storms moving forward will be across Hudspeth County and perhaps southern Otero County. There could be a storm or two that become strong to severe with small hail and strong winds being the threats of note. However, within any storm that develops, with the high dewpoint depressions and DCAPE of around 1500 J/kg, gusty winds will be possible. Particularly along any outflow boundaries that develop, where as we saw yesterday, gusts to 40-45mph will be possible. These could hold together and travel well away from the storm, so the entire area will have to be monitored for gusty outflow winds later this afternoon. This may result in areas of blowing dust with visibility reductions to 3 miles possible. Rainfall totals aren`t expected to be much, though up to 0.25" will be possible in the strongest cells. High temperatures are already very warm, with readings in the upper 80s to lower 90s at this hour. Expect highs to top out in the low to mid 90s across the lowlands. It`s important to note that if an outflow boundary moves through your location, it will quickly cool temperatures down. Storm chances will come to an end by sunset this evening as the moisture is pushed off to the east due to the movement of the upper level ridge. Gusty winds will also subside after sunset, and clouds will gradually clear across eastern areas. An upper level trough move through the Borderland on Saturday. This will lead to the development of a strong lee side low to our northeast that will tighten our pressure gradient at the surface. A 500mb jet streak of 40-50kt will also move through ahead of the trough. This will lead to increasing westerly winds across the entire CWA Saturday afternoon. While speeds will remain below Advisory criteria, it will be notably windy with even some patchy blowing dust possible. Since relative humidities will plummet into the single digits tomorrow as the moisture moves out, these dry conditions combined with gusty winds will create a high fire danger. High temperatures on Saturday will cool several degrees into the mid to upper 80s as the trough pushes through. && .LONG TERM... The long term picks up on Sunday. We will continue to be at the base of a western trough, so we will continue to be dry with breezy afternoon and early evening conditions and we will see more of the same on Monday. The winds both Sunday and Monday will be less than we will see on Saturday. High temperatures both days will be near seasonal averages. On Tuesday another short wave trough will dash across northern New Mexico. This system will be missed timed to give us some strong winds, as it will swing through during the overnight hours. In addition a cold front will be hung up in the east plains of New Mexico and that will help prevent a lee side trough from getting set up. The upshot of all of this will be another breezy afternoon with seasonal high temperatures on Tuesday. On Wednesday an upper level ridge will begin to nose into the region, while at the surface an east push will be lurking just to our east. The winds on Wednesday will finally take a break and our high temperatures will be a few degrees below average. On Thursday, the east push (I don`t really want to call a cold front, since it is not very cold on the back side of wind shift) will move into the area and this will allow some moisture to trickle back into the region. There probably won`t be enough moisture to give us a rain chance on next Thursday, but like today there will be just enough moisture for next Friday to give us a chance of afternoon or evening thunderstorms. Fingers crossed that we can get more than just wind and dust. && .AVIATION...Mostly VFR conditions expected through the period; however, SHRA/TS will be possible in the mountains and east of the Rio Grande valley through 01Z. The best chance for storms will be east of ELP, so have left out mention of TS in the TAF for now due to low confidence. The main threat will be gusty outflow winds from these storms, which will have the potential to move and last long enough to impact most terminals, with LRU/ELP having the greatest threat. This will create variable wind directions with gusts up to 40KT possible. This is highlighted in ELP`s TAF since confidence is higher that TS will develop somewhere S/SE of ELP after 21Z and push an outflow to the N/NW. This may also result in areas of blowing dust and reduced VIS to 2-4SM. Otherwise, expect SW winds of 12-20G25KT at all TAF sites through 03Z before subsiding overnight. CIGs will be SCT060-100 BKN200 over mountains and east of the Rio Grande, then gradually clearing overnight. && .FIRE WEATHER... Showers and storms are already ongoing across the eastern slopes of the Gila Region and Sacramento Mountains. Storm chances will also develop for southeastern areas this afternoon as convection moves out of Mexico. The best chance for storms will be over Hudspeth County, but most locations have the potential to see gusty, erratic outflow winds push through with variable wind directions. Storm chances will come to an end by sunset as the moisture moves off to the east. An upper trough will move into the area on Saturday increasing westerly winds. Combined with min RHs dropping to 5-10 percent, most locations will see Red Flag Warning conditions during the afternoon, thus a Red Flag Warning has been issued for NM Fire Zones 110, 111, 112, and 113. TX Fire Zones 055, 056 could briefly see spotty Red Flag conditions as well, but confidence is lower due to today`s rain chances. Winds will weaken a bit for Sunday and Monday, though some afternoon breezes will remain possible. Even though speeds look to remain below Critical thresholds for now, there could still be isolated Red Flag conditions for some locations, though it likely won`t be widespread or for a long enough duration to warrant a Warning. Dry conditions will remain in place through the first half of next week with min RHs below 12 percent. Vent rates will be Very Good to Excellent. && && .PRELIMINARY POINT TEMPS/POPS... El Paso 65 89 62 88 / 10 0 0 0 Sierra Blanca 57 86 55 82 / 40 0 0 0 Las Cruces 59 87 55 88 / 0 0 0 0 Alamogordo 60 87 54 85 / 10 0 0 0 Cloudcroft 47 64 42 61 / 10 0 0 0 Truth or Consequences 56 85 55 85 / 0 0 0 0 Silver City 52 75 50 75 / 0 0 0 0 Deming 52 86 49 86 / 0 0 0 0 Lordsburg 52 85 49 83 / 0 0 0 0 West El Paso Metro 63 87 61 86 / 0 0 0 0 Dell City 56 88 54 86 / 30 0 0 0 Fort Hancock 59 92 57 88 / 30 0 0 0 Loma Linda 57 83 55 79 / 20 0 0 0 Fabens 61 90 60 88 / 20 0 0 0 Santa Teresa 58 87 55 85 / 0 0 0 0 White Sands HQ 63 86 60 85 / 0 0 0 0 Jornada Range 57 85 54 83 / 0 0 0 0 Hatch 57 87 53 85 / 0 0 0 0 Columbus 58 87 55 85 / 0 0 0 0 Orogrande 59 86 55 84 / 10 0 0 0 Mayhill 50 75 47 74 / 10 0 0 0 Mescalero 50 74 45 72 / 10 0 0 0 Timberon 45 71 43 70 / 10 0 0 0 Winston 42 77 42 78 / 0 0 0 0 Hillsboro 53 82 52 82 / 0 0 0 0 Spaceport 55 85 52 83 / 0 0 0 0 Lake Roberts 46 76 43 77 / 0 0 0 0 Hurley 47 79 44 80 / 0 0 0 0 Cliff 44 84 42 85 / 0 0 0 0 Mule Creek 50 77 48 78 / 0 0 0 0 Faywood 52 79 50 79 / 0 0 0 0 Animas 50 86 48 85 / 0 0 0 0 Hachita 52 85 50 84 / 0 0 0 0 Antelope Wells 52 84 50 83 / 0 0 0 0 Cloverdale 51 80 49 78 / 0 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...Red Flag Warning from noon to 8 PM MDT Saturday for NMZ110>113. TX...None. && $$
National Weather Service Sioux Falls SD
1034 PM CDT Fri May 7 2021 .SHORT TERM...(This Evening through Saturday) Issued at 231 PM CDT Fri May 7 2021 Quiet conditions prevailing across the region this afternoon with north or easterly winds occasionally on the breezy side. These quiet conditions continue into the the bulk of the overnight hours with increasing clouds as well as winds helping to mitigate the frost concerns of the last several nights. Changes begin to get introduced toward the daybreak hours Saturday as a mid/upper level cutoff low sinks southeastward out of the Pac NW. Guidance still consistent in keeping the main low level baroclinic zone and axis of instability to our south and west with broader synoptic lift and favorable mid-level WAA further to the east over our more immediate area. This should help drive an eastward expanding area of showers toward the James River by mid morning and I-29 corridor by early to mid afternoon. Could see a few lead lighter showers out ahead of the main area of showers, however soundings suggest that a dry easterly flow may help delay the onset of any meaningful precipitation. Widespread showers look likely for most locations for the afternoon and at least portions of the evening hours Saturday with some weak instability for locations near and south of I-90 perhaps allowing some embedded thunder activity as well. Shower coverage should become more contracted by the second half of the overnight into Sunday morning but will likely see as least some lingering activity within a zone of mid-level convergence and a northward lifting right entrance jet streak. Rain amounts still look rather disappointing in terms of any significant impact to the ongoing drought, although any moisture is welcome. Ensemble suites from the GFS, ECMWF and Canadian all show fairly high odds for most locations to receive over a tenth of an inch while fairly low odds of receiving over a half an inch. This clustering of a couple/few tenths of QPF is also noted in ensemble plumes for various locations. The 12z HRRR is very unimpressive in terms of QPF but seems to be an outlier at this point (although with an easterly fetch, some preference is given toward lower QPF solutions). Outside of the rain showers Saturday and Sunday, conditions look rather miserable with temperatures Saturday struggling to get into the lower 50s with only slight improvement for Sunday. Easterly winds Saturday will also gusts between 25-35 mph at times with lighter, although still somewhat elevated northeasterly winds for Sunday. .LONG TERM...(Saturday Night through Friday) Issued at 231 PM CDT Fri May 7 2021 Jet stream sinks south for early next week and should help void our region of precipitation chances. This will also help keep temperatures on the cool side of normal, or generally mid 50s to lower 60s. Another wave lifts through Tuesday night into Wednesday but with the main moisture plume still buried well to our south, don`t expect much more than perhaps some light showers and added cloud cover with this disturbance. Temperatures still running a few degrees either side of 60 degrees are expected. Better upper level ridging arrives for the later half of the work week with temperatures moderating back into the 70s. With induced southerly return flow, increasing dewpoints/moisture may also help advect in better instability and thunderstorm chances by next weekend. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1034 PM CDT Fri May 7 2021 Primary concern for the TAFs is MVFR and possible IFR conditions with band of rain expected late Saturday into Saturday night. Clouds will overspread the area through the night. As the frontal band begins to develop, clouds will lower through morning and fall below 3000 ft during the early afternoon. As rain falls through the afternoon, light fog is expected to develop with the visibility of 3-5 SM. Ceilings will also fall below 2000 ft. It is possible IFR ceilings could develop in the late afternoon and evening as moisture becomes trapped beneath a strong frontal inversion located around 10 ft. Even after the heavier rain ends, light drizzle and fog producing MVFR ceilings and visibility are likely through Saturday night at all TAF locations. In addition to the rain, winds will increase through the night with east to southeast winds of 10 to 20 kts much of Saturday and into Saturday evenings. Gusts of 25 to 30 kts are expected across the area. An inverted trough will move toward KHON and KFSD after 00Z Sunday. As the trough approaches winds will gradually weaken to around 10 kts toward 06Z Sunday. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...Kalin LONG TERM...Kalin AVIATION...Schumacher
National Weather Service Wilmington OH
922 PM EDT Fri May 7 2021 .SYNOPSIS... A disturbance will work through the region this evening. A larger system will bring widespread moderate to heavy rainfall to the region Saturday night through Sunday evening. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... A shortwave upper level trough is currently moving southeastward through the Ohio Valley late this evening as it rounds the base of a broad upper level trough. This setup is very similar to yesterday at this time. Weakening widespread shower activity has been observed ahead of the approaching upper level vorticity max. Showers are expected to continue diminishing in intensity and coverage as the night progresses, eventually giving way to dry conditions in most locations by 2AM as DCVA decreases. Mention of hail has been removed from the grids because low level lapse rates and instability has dwindled after sunset. Cold northwesterly winds will continue advecting in cold air from the northwest behind the showers. The coldest lows are forecast to be in southwest Ohio/eastern Indiana/northern Kentucky where some clearing skies and calming winds may occur late overnight. These conditions may briefly allow frost development before sunrise and have been highlighted by a Frost Advisory. Elsewhere, lows are expected to be in the upper 30s to near 40 where more wind and clouds persist. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Expect dry conditions for most of the daytime hours on Saturday. As warm front moves into the area expect rain to develop across the region. Instability is very limited and therefore kept any thunder mention out of the forecast. Least amount of confidence is southeastern portions of the forecast area across the lower Scioto Valley and into northern Kentucky as model trends have been hinting at a more northern solution with the precipitation. Temperatures are expected to reach into the 50s to around 60 degrees for highs on Saturday and drop down into the 40s Saturday night. Temperatures will start to warm some later in the night as the warm front moves northward. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Warm front will extend across the area will low pressure approaching the region at the beginning of the period. Spread in position has narrowed a bit with the 12Z guidance suite, but still about a 100 mile difference which given the strong gradient associated with this system will have a substantial impact on the forecast both in terms of temperature and where greater precipitation amounts occur. Forecast fairly closely follows a multi model blend, although it is a bit uncomfortable that the 12Z ECMWF (as well as its ensemble mean) along the the extended run of the 15Z RAP (through 09/18Z) maintain the more southerly position. So showers or rain, depending on where you are relative to the boundary, will be ongoing at the beginning of the period. Looks like there is potential for a bit of a lull in precipitation towards midday but then increasing again in the afternoon as the low moves into the area. Precipitation will continue into the evening and then end fairly quickly as the low and frontal system move off to the east. Expect a swath of 1 to 2 inches of rain for the entire event. High pressure will build in for Monday and Tuesday and likely continue to influence the region into Wednesday. ECMWF and CMC have trended towards less amplitude with a short wave tracking through the Plains midweek. So it is faster as it passes the area with little or no surface reflection. GFS still maintaining a stronger system with a low passing just south of the area later in the week. Given uncertainties, have chance PoPs for Wednesday night and Thursday. Below normal temperatures will continue through the period. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... A ~6000ft AGL cumulus field and scattered showers are moving across the Ohio Valley this evening. VFR conditions are being observed everywhere except for a few very brief and isolated MVFR visibility dropouts in the strongest showers. Cumulus and shower activity will drop off later this evening with the loss of daytime heating and give way to mostly clear skies almost everywhere. The only exception to the clearing may occur across central Ohio (possibly impacting KCMH/KLCK) where some lower MVFR stratus is possible late overnight. By around 1200Z, KCMH/KLCK should experience clearing of any MVFR ceilings and VFR conditions persist the rest of the day at all sites. High and middle level clouds will then thicken Saturday afternoon and Saturday night ahead of the next weather maker on Sunday. Westerly/northwesterly winds from 5-10 knots are expected the entire TAF period until Saturday evening when winds become light and variable. .OUTLOOK...Rain is expected Saturday night through Sunday night MVFR to IFR ceilings can be expected with LIFR ceilings possible. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...Frost Advisory from 3 AM to 10 AM EDT Saturday for OHZ042-060- 061-070>072-077>081. KY...Frost Advisory from 3 AM to 10 AM EDT Saturday for KYZ089>100. IN...Frost Advisory from 3 AM to 10 AM EDT Saturday for INZ050-058- 059-066-073>075-080. && $$ SYNOPSIS...Novak NEAR TERM...Campbell SHORT TERM...Novak LONG TERM... AVIATION...Campbell
Area Forecast Discussion
National Weather Service Jackson MS
852 PM CDT Fri May 7 2021 .UPDATE... Updated for evening discussion. && .DISCUSSION... Have made some adjustments to the forecast this evening as some showers and isolated thunder over southeastern AR has held together over the last few hours. HRRR and NAMNest are both consistent with the deterioration of the precip...but still bring it across the river and into the northern portion of the forecast area. Have also adjusted the overnight lows as the clouds associated with these showers/the upper disturbance will likely get in the way of efficient radiational cooling under the ridge axis in the east. Prior discussion below: Tonight: As the longwave trough axis begins to swing up the Atlantic seaboard, the surface ridge will continue to build in the wake. NW flow aloft will persist overnight. The low-level ridge axis builds east along the northern Gulf Coast, SW return flow will begin to pick up across the Delta. As the 1020mb sfc ridge is progged E, expect winds to remain generally light overnight. Other than some high clouds, any disturbance/rain chances will be well off to the N over the Ozarks/Mid-South. Lows will fall some 5-10 degrees below normal, especially in the E, mainly in the mid 50s W to upper 40s to the E. Saturday: Another deepening trough & cyclogenesis will be developing, leading to progged strong deepening surface low across the Central Plains. In response a broad increasing pressure gradient will exist across the area. NE lifting warm front will also increase WAA/moisture advection. Dewpoints will begin to increase from SW to NE in the low-mid 50s to low 60s by the afternoon while drier in the upper 40s in the NE. Even with some drier air & winds beginning to increase across the Delta, there isn`t good juxtaposition of humidity & winds for fire danger issues. Even with some subtle mid- high clouds, increasing low-level thermal warmth & efficient mixing potential will help highs warm slightly above normal in the low-mid 80s. Gradient winds could be gusty across the Delta, sustained around 15-20mph, with some brief higher gusts. This looks just below any need for mention in the HWO. /DC/ Saturday night through Thursday night...Surface high pressure will continue over the area Saturday night, but will weaken on Sunday out ahead of an approaching shortwave. High temperatures will climb into the 80s on Saturday and Sunday. Beyond Sunday, a wet pattern is going to set up across the ArkLaMiss. A short wave and associated cold front will approach the Delta Sunday and with increasing moisture, thunderstorms will develop to the west and move into the Delta Sunday evening. With sufficient instability and deep layer sheer, some of these storms could be strong to severe with hail and damaging wind gusts the primary threat. The severe threat will diminish during the overnight hours, as the storms progress eastward and instability weakens. A slight risk is already in effect for much of the delta. The Showers and thunderstorms will continue eastward across the area Sunday night into Monday morning, with the bulk of the storms moving southeast of the area by noon on Monday. Weak high pressure will briefly build in on Monday and Monday night, but showers will continue to be possible across the area. The front will push back north into the area on Tuesday, with increasing chances for thunderstorms once again. The front will become stationary across the area Tuesday night, with showers and storms continuing across portions of the area. The global models differ some on how far north the boundary will get during this period, and this will dictate the areas that will receive the heaviest rainfall amounts. A stronger short wave will move across the area on Wednesday and this will drag a cold front across the area Wednesday evening. Currently it looks like heavy rainfall and possible flash flooding will be the biggest threat during this period, and will have to continue to be monitored. High pressure will build back in across the region Wednesday night and continue into the weekend./15/ && .AVIATION... 00Z TAF discussion: VFR through the pd...with winds showing some variability again as the surface ridge slides to the east. Southerly flow will reestablish tomorrow...and some guidance indicating some gusts in the 20-25 kt range mixing down through the afternoon. && .PRELIMINARY POINT TEMPS/POPS... Jackson 52 83 62 85 / 0 0 0 22 Meridian 50 82 59 85 / 0 0 0 9 Vicksburg 54 84 65 85 / 1 0 1 37 Hattiesburg 52 83 60 86 / 0 0 0 7 Natchez 56 84 64 84 / 0 0 0 24 Greenville 55 84 66 83 / 23 1 1 59 Greenwood 54 81 65 83 / 20 0 1 49 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ HJS
National Weather Service Jackson KY
1057 PM EDT Fri May 7 2021 .UPDATE... Issued at 1057 PM EDT FRI MAY 7 2021 The initial batch of showers that affected more of the northern half of the forecast area has exited off to the east southeast through this evening. Meanwhile, additional activity is now moving across the southern half of our area. The Low level dry air is definitely hampering rainfall amounts, as most locations have only seen a few to several hundredths of an inch in the north, with locations to the south only measuring in places. Just northeast of the forecast area, a broken line of deeper convection has been training closer to some better convergence that has aligned ahead of the surface cold front, which is approaching the Ohio River. These cells have weakened as they move east southeast across southern Ohio/northern Kentucky. Most locations in between the I-64 corridor and just south of the Mountain Parkway are now dry. Have made some PoP adjustments accordingly, using radar trends, as well as some of the higher resolution model guidance. Better PoPs will remain confined to the south and along our north and northeastern border for the next few hours, with a gradual migration of the PoPs towards our southeast with time, as the cold front moves in from the northwest after midnight. For temperatures, did raise the lows a bit across our southeast, where the combination of lingering cloud cover and some minor post-frontal mixing looks to keep better radiational cooling in check. Have generally let the rest of the forecast low temperatures ride, with a small window of frost opportunity in our Bluegrass counties, as skies clear out and winds eventually lighten towards dawn. Updates have been sent. UPDATE Issued at 713 PM EDT FRI MAY 7 2021 Shower activity is headed our way this evening, as the combination of a short wave trough and surface cold front transit the Ohio Valley. Most of the lightning has remained well to our north and northwest, where temperatures are colder aloft, and slightly better low level moisture resides. The latest RAP soundings show very little instability across our northern areas this evening, and given that the core of the short wave trough will mainly stay on the north side of the Ohio River, have removed thunder from the forecast. Also made some PoP adjustments based on the latest higher resolution model guidance as well as the radar mosaic trends. Will assess the forecast lows a bit later this evening. Updates are out. && .SHORT TERM...(This evening through Saturday night) Issued at 525 PM EDT FRI MAY 7 2021 A shortwave trough embedded in a large scale upper trough over the eastern CONUS was over the upper Great Lakes late Friday. It will rotate through the upper trough, reaching the mid Atlantic states by Saturday afternoon. As it passes by to our northeast, it will support a cold front which will move south through the forecast area tonight. There is very little moisture advection/recovery able to occur ahead of the front. However, thunderstorms have developed upstream over IN. Models show some very weak instability persisting over our area as the system arrives this evening underneath unusually cold air aloft, and have still included a slight chance of thunder. Aside from thunderstorms, there is a likelihood of showers for most of the area tonight as the front arrives. Behind the front, significant drying tries to work in from the north overnight. It appears skies will start to clear from the north, posing a threat of frost in the chilly post frontal air mass in our far northern counties if winds can diminish. The front will stall from AR to GA on Saturday. Low pressure moving east from the plains to the Ohio Valley will pull the front back northeast into KY on Saturday night. Models show a possibility for an area of rain moving northeast over our area in the isentropic lift ahead of the front on Saturday night. The NAM and GFS are very scant on precip, but the ECMWF still has more substantive amounts. Have backed off some on the POP from the previous forecast considering the GFS and NAM. .LONG TERM...(Sunday through Friday) Issued at 500 PM EDT FRI MAY 7 2021 A fairly active extended is in store, with unsettled weather expected to finish out the weekend Sunday and continue into the workweek. We start off in the upper levels with heights falling as a wave works in from the west. At the surface, an area of low pressure resides over the Middle Mississippi Valley, with an associated warm front stretched across the Ohio Valley just to our north and a cold front extending down into the Southern Plains. With the warm front to our north, that`s where the best rain chances will be earlier on, though these chances will spread further south going through the day. Going into Sunday night, the surface low continues to push northeast, dragging a cold front down through the state along with widespread precip chances. Thunderstorms are also possible late Sunday afternoon through Sunday night, with thunder chances decreasing into Monday morning as instability decreases. Winds could also get pretty gusty in the afternoon Sunday as a fairly stout low level jet passes over. Temperatures Sunday are the warmest they will be through the entire rest of the period. Highs Sunday will get into the mid and possibly upper 70s as southerly to southwesterly winds help to advect in warmer air behind the warm front. Lows Sunday night will stay relatively mild in the upper 40s to low 50s. Through Monday, this front continues to push south and high pressure tries to nudge in behind it. Rain chances look to decrease through the day. Highs will be cool in the low 60s as northwesterly flow ushers in cooler air behind the front. Monday night looks to have skies beginning to clear late under the influence of high pressure, while lows dip into the upper 30s to the low 40s. The NBM has finally come on board with the idea of dry weather through Tuesday. Beyond Tuesday there`s considerably more uncertainty. An upper level trough moves east towards the Ohio Valley over the day Wednesday and into Thursday, supporting an associated wave at the surface. There are some timing differences, but it appeared as though there was more disagreement over strength. Some guidance was stronger and had precip moving into the area Wednesday through Thursday, while other guidance had a weaker wave and had precip staying off to our south. Did delay the onset of rain on Wednesday from what the NBM had populated, after looking at model trends and ensemble probabilities. However, beyond Wednesday, given the distance out in the forecast, along with the lack of consistency from model to model or run to run, stayed close to the NBM. At this point, the forecast has rain, and maybe a few thunderstorms, moving into the area Wednesday afternoon with sticking around Thursday, before eventually exiting Friday. However, expect that this will likely need further refinement as more details are worked out and models, hopefully, come into better agreement. Temperatures Tuesday onward stay cool, with highs staying in the 60s and lows generally in the 40s, aside from maybe a few upper 30s Tuesday night. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 748 PM EDT FRI MAY 7 2021 A passing upper level disturbance and surface cold front will bring another round of shower activity to the area tonight. The better areal coverage of the showers looks to occur along and northwest of a line from KSJS to KJKL. Ceilings will lower to between 3 and 5k feet agl; however, still expect VFR conditions to generally hold on. As the front gradually exits the area between 09 and 12z, some of the model guidance indicates some MVFR ceilings forming behind the front across southeastern Kentucky, but confidence is not high enough to include, as this would affect locations from KSJS to KLOZ. Clouds will decrease from northwest to southeast early Saturday morning, before increasing once again from the southwest by the end of the period. Winds will remain west to west southwest at around 5 kts tonight, before shifting to the northwest behind the cold front. && .JKL WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 5 AM to 9 AM EDT Saturday for KYZ044-050>052. && $$ UPDATE...GEOGERIAN SHORT TERM...HAL LONG TERM...HAS AVIATION...GEOGERIAN
Area Forecast Discussion
National Weather Service Marquette MI
744 PM EDT Fri May 7 2021 .SHORT TERM...(This evening through Saturday) Issued at 410 PM EDT FRI MAY 7 2021 WV imagery and RAP analysis indicated a mid/upper level low near James Bay with a broad trough through the Great Lakes into the southeast CONUS. The strong shortwave trough that brought pcpn across Upper Michigan into this morning has exited into northern lower Michigan. Even though a sfc ridge from Manitoba into MN was building into the area, some diurnal light showers remained over central Upper Michigan where 700 mb temps to around -15C have resulted in steep low level lapse rates. Tonight, expect any remaining -shra to diminish with the loss of daytime heating diminishes. Favorable radiational cooling as skies become clear to partly cloudy will allow temps to drop into the lower to mid 20s well inland west and to th lower 30s near the Great Lakes. Another weak shrtwv may bring some increasing clouds north late. Saturday, ridging will continue to build into the area. However, enough cold air will remain (700 mb temps to -13C) for another round of bkn inland diurnal cu some some light showers sprinkles central, closest to the stronger low level convergence. Otherwise, with 850 mb temps in the 0C to -4C range from sw to e, temps will climb into the mid 40s to around 50 north and to the mid 50s near the WI border. .LONG TERM...(Saturday night through Friday) Issued at 310 PM EDT FRI MAY 7 2021 A strong blocking ridge over northern mid-Atlantic will keep an upper level low pressure over the Hudson Bay area though early next week, with ridging in the western U.S and troughing downstream over the Great Lakes. This will keep things seasonably cool through the end of the weekend with northwesterly flow. Thereafter deterministic models indicate the ridge will break down and the trough finally kicks east. WPC Ensemble fuzzy clusters all show the negative height anomalies finally kicking east mid-week next week as well but not showing any significant positive height anomalies over the central U.S. Models advertise a shortwave moving through the region on Monday but with the strongest forcing staying south of the area. While we continue under the influence of the trough through this weekend into early next week expect seasonably cool weather with mainly dry and cool northerly flow. 850mb temperatures will remain in the 0 to -7C range with reinforcement of the colder temperatures behind the aforementioned shortwaves. This could bring increasing instability and trigger light showers over the interior but overall the air will be pretty dry with deep inverted-v soundings. The main concern will be fire weather conditions as we have not reached green- up yet with the main concern being low afternoon RHs. Warm air advection takes over on Tuesday with temperatures warming into the 50s away from the Great Lakes and eventually 60s by Wednesday and Thursday. Precipitation chances increase for Thursday with a shortwave progressing through the area. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 738 PM EDT FRI MAY 7 2021 VFR conditions are expected at the terminals through the period. More diurnal cu development is likely during the day on Saturday under a cool airmass, especially at KSAW and maybe KCMX, but again VFR conditions will prevail. Light lake breeze winds could also develop on Saturday. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 410 PM EDT FRI MAY 7 2021 Light winds below 20 knots are expected into next week across Lake Superior. However, the period of slightly higher winds to near 20 knots is expected late Sunday into Monday as another weak cold front moves through the area. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...NL AVIATION...Voss MARINE...JLB
Area Forecast Discussion...UPDATED
National Weather Service Nashville TN
806 PM CDT Fri May 7 2021 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Weak surface trough sagging southward toward our area this evening. Radar does depict some light shower activity heading toward our northern Plateau. Not much ground truth however until you move further north and across northern KY. Trajectory of the activity is in line with the current fcst, however. Later tonight...a warm front will begin to work northward. this will allow a chance of showers to begin to return toward dawn for our western counties. Latest Hrrr is somewhat in line with this solution. Fcst covers this possibility well. thus, no changes to the current fcst. && .AVIATION... 00Z TAF DISCUSSION. Expect VFR conditions at all sites through the overnight hours with gusty winds ending early this evening. Light showers will be possible in the morning, with better chances occurring in the afternoon to early evening. Impacts to VIS and CIGS should be minimal as shower intensity is not expected to be that great. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......21 AVIATION........05